(a) Field of the Invention
The present invention relates to a plasma display device and a driving method thereof and more particularly to a driving method that manipulates the grayscale values of an input video signal.
(b) Description of the Related Art
In a plasma display device, a video signal of one frame input to the plasma display device, i.e. an input video signal, is divided between a plurality of subfields each having a corresponding weight. Grayscales are expressed according to an on/off state of the subfields and a combination of weights of the on-subfields. Each subfield includes a reset period, an address period, and a sustain period. The reset period is for initializing the state of each discharge cell so as to facilitate an addressing operation on the discharge cell. The address period is for selecting turn-on/turn-off cells (i.e., cells to be turned on or off) and accumulating wall charges in the turn-on cells (i.e., addressed cells). The sustain period is for causing a discharge for displaying an image on the addressed cells.
However, when as described above data from the input video signal of one frame is divided between a plurality of subfields and grayscales are displayed according to an on/off state of the subfields, a false contour may be generated due to the characteristics of human visual perception. That is, when a moving image is displayed, a false contour phenomenon may occur in which a grayscale that is different from an actual one is perceived by human eyes.
In addition, when the grayscales are displayed according to the on/off state of the subfields, if the number of the on-subfields is small, then a small amount of priming particles are generated, and accordingly, a sufficient discharge may not be generated.